Relativistic jets of active galactic nuclei have been known to exist for 100 years. Blazars with
their jet pointing close to our line of sight are some of the most variable and extreme objects …

We analyze the parsec-scale jet kinematics from 2007 June to 2013 January of a sample of
γ-ray bright blazars monitored roughly monthly with the Very Long Baseline Array at 43 GHz …

The author presents a model for variability of the flux and polarization of blazars in which
turbulent plasma flowing at a relativistic speed down a jet crosses a standing conical shock …

We present results from monitoring the multi-waveband flux, linear polarization, and parsec-
scale structure of the quasar PKS 1510− 089, concentrating on eight major γ-ray flares that …

Powerful radio jets from active galactic nuclei are thought to be powered by the accretion of
material onto the supermassive black hole (the 'central engine'),. M87 is one of the closest …

We present ten years of R-band monitoring data of 31 northern blazars which were either
detected at very high-energy (VHE) gamma rays or listed as potential VHE gamma-ray …

It is widely accepted that strong and variable radiation detected over all accessible energy
bands in a number of active galaxies arises from a relativistic, Doppler-boosted jet pointing …

The bright blazar OJ 287 routinely parades high brightness bremsstrahlung flares, which are
explained as being a result of a secondary supermassive black hole (SMBH) impacting the …

We analyze the multi-frequency behavior of the quasar 3C 454.3 during three prominent γ-
ray outbursts: 2009 Autumn, 2010 Spring, and 2010 Autumn. The data reveal a repeating …

We analyze the behavior of the parsec-scale jet of the quasar 3C 454.3 during pronounced
flaring in 2005–2008. Three major disturbances propagated down the jet along different …